Tuning Physical Properties of Tomato Puree by Fortification with Grape Skin Antioxidant Dietary Fiber

Analyzing and simulating heat transfer and designing a shell and tube heat exchanger for the pasteurization process of tomato paste: A CFD study

Pasteurization is a vital process to destroy harmful enzymes. This process is very critical to obtain quality tomato paste. In this study, Computational Fluid Dynamics (CFD) has been used to design a shell and tube heat exchanger on an industrial scale and to simulate heat transfer in order to visualize this process and present it to the industry. In this research, a three-dimensional CFD model was simulated using ANSYS FLUENT commercial software. Also, using the Herschel-Bulkley model, the behavior of viscosity in the pasteurization process of tomato paste has been explained. In this stage of the production line, the tomato paste enters a shell and tube heat exchanger at 65 °C and reaches 80 °C at the outlet. Compared with the experimental data, the output temperature of tomato paste predicted by CFD simulation reached 79 °C. In addition, thermophysical properties of tomato paste were measured, and these exact values were used for simulation. Also, the evaluation of this heat exchanger with three hot water inlet mass flow rates has been done in order to provide the results to the factory to avoid spending more energy. And the simulation results showed that the output temperature of tomato paste at three different mass flow rates did not change less than the mass flow rates measured in the factory, and also the output visualizations from this research can be suitable for presenting to the industry and benefiting from them.

Study of rheological properties of açai berry pulp: an analysis of its time-dependent behavior and the effect of temperature

The industry of açai-based products has been growing in the last few years. Knowledge about the physical properties of açai pulp, including its rheology, is essential to the optimization of industrial processes. This work presents the rheological behavior of açai berry pulp in relation to the effects of shear rate, temperature, and time of shearing. The entire study was carried out in the temperature range of 10-70 °C. Açai pulp showed a non-Newtonian, pseudoplastic, and time-dependent behavior. Four upward and backward shear rate cycles were evaluated, resulting in complex hysteresis loops, in which thixotropy and anti-thixotropy zones were observed. Downward flow curves could be satisfactorily represented by the Power-Law rheological model. The stress profiles as a function of shear rate obtained in the first upward curves suggest a breakdown of the initial fluid structure at low shear rates. Tests were also carried out at a constant shear rate of 20 s^-1 and, in this case, the Weltman model of thixotropy satisfactorily fit the experimental data. The activation energy, which was calculated by the Arrhenius equation, was 29.0 kJ/mol. The achievements of this work may be useful to further studies about açai pulp rheology and may contribute to process design in the açai industry.

Waste grape skins: evaluation of safety aspects for the production of functional powders and extracts for the food sector

Skin powders and aqueous alcohol extracts were obtained from waste marcs from different grape varieties (Barbera, Nebbiolo, Pinot Noir, Chardonnay, Moscato and Müller-Thurgau). Both skins and extracts were analysed for the content of chemical contaminants: ochratoxin A (OTA), biogenic amines (BIAs), pesticides and metals. OTA was detected in low concentrations in Barbera, Moscato and Nebbiolo skins, but only in Barbera and Moscato extracts. Cadaverine, putrescine, ethanolamine and ethylamine were found in extracts at very low levels, while potential allergenic amines, tyramine and histamine, were never detected. Different pesticides were present in both skins and extracts. Pb and Cd were found in trace only in the powders, and K, Ca and Mg were the most abundant elements in both skin powders and extracts. Concentrations of the different contaminants were related to fibre content or total phenolics content of powders and extracts, respectively, in order to evaluate their use in the food sector.